//! Process management system calls
//! SPDX-License-Identifier: MPL-2.0

const std = @import("std");
const SyscallReturn = @import("../return.zig").SyscallReturn;
const SyscallError = @import("../error.zig").SyscallError;
const Context = @import("../context.zig").Context;
const Pid = @import("../context.zig").Pid;
const VirtAddr = @import("../context.zig").VirtAddr;

/// Fork a new process
pub fn sys_fork(ctx: *Context) SyscallReturn {
    _ = ctx;
    // TODO: Implement fork
    // This would involve:
    // 1. Creating a new process structure
    // 2. Copying memory space
    // 3. Setting up new page tables
    // 4. Copying file descriptors
    // 5. Setting up parent-child relationship
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Create a new process with vfork semantics
pub fn sys_vfork(ctx: *Context) SyscallReturn {
    _ = ctx;
    // TODO: Implement vfork
    // Similar to fork but shares memory until exec
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Execute a new program
pub fn sys_execve(
    filename_addr: VirtAddr,
    argv_addr: VirtAddr,
    envp_addr: VirtAddr,
    ctx: *Context,
) SyscallReturn {
    _ = filename_addr;
    _ = argv_addr;
    _ = envp_addr;
    _ = ctx;
    // TODO: Implement execve
    // This would involve:
    // 1. Loading the new executable
    // 2. Setting up new memory layout
    // 3. Parsing arguments and environment
    // 4. Setting up initial stack
    // 5. Jumping to entry point
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Exit the current process
pub fn sys_exit(exit_code: i32, ctx: *Context) SyscallReturn {
    _ = exit_code;
    _ = ctx;
    // TODO: Implement exit
    // This would involve:
    // 1. Cleaning up process resources
    // 2. Notifying parent process
    // 3. Updating process state
    // 4. Scheduling next process
    // Note: This syscall should not return
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Exit all threads in the process group
pub fn sys_exit_group(exit_code: i32, ctx: *Context) SyscallReturn {
    _ = exit_code;
    _ = ctx;
    // TODO: Implement exit_group
    // Similar to exit but affects all threads
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Wait for child process to change state
pub fn sys_wait4(
    pid: Pid,
    wstatus_addr: VirtAddr,
    options: i32,
    rusage_addr: VirtAddr,
    ctx: *Context,
) SyscallReturn {
    _ = pid;
    _ = wstatus_addr;
    _ = options;
    _ = rusage_addr;
    _ = ctx;
    // TODO: Implement wait4
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Send signal to a process
pub fn sys_kill(pid: Pid, signal: i32, ctx: *Context) SyscallReturn {
    _ = pid;
    _ = signal;
    _ = ctx;
    // TODO: Implement kill
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}

/// Create a new process/thread with clone
pub fn sys_clone(
    flags: u64,
    stack_addr: VirtAddr,
    parent_tid_addr: VirtAddr,
    child_tid_addr: VirtAddr,
    tls_addr: VirtAddr,
    ctx: *Context,
) SyscallReturn {
    _ = flags;
    _ = stack_addr;
    _ = parent_tid_addr;
    _ = child_tid_addr;
    _ = tls_addr;
    _ = ctx;
    // TODO: Implement clone
    return SyscallReturn.error_return(SyscallError.ENOSYS);
}